Well sadly yes, criminal or coruptor using the money and buy bitcoin for money laundry. I'm sure at least 1 person already do that out there but i think people already smart nowdays and police are know about bitcoin and can detect it if the suspect caught using bitcoin or have a bitcoin wallet.
It was right that criminals and other corruptor is really using bitcoins as a money laundering tool but cryptocurrency and fiat are just the same in terms of transactions, but basically bitcoins is very helpful for the community because it can make peoples lives change in to better.